RELATION SUPRARENAL GLANDS TO CIRCULATION 195 



after its gross pharmaco'dynamic effects have disappeared, seems suf- 

 ficiently demonstrated. Weiss and Harris have reported an investigation 

 which has been frequently referred to in this connection. In the frog 

 one iliac artery was ligated and epinephrin was injected into the general 

 circulation. Comparative studies were made in the hlood-vessels of the 

 webs of both feet. After the vasoconstrictor effect in the non-ligated limb 

 had entirely disappeared the ligature was removed from the artery and 

 the blood allowed to pass to the other web. An intense vasoconstriction 

 now appeared in the previously ligated side. It has also been reported 

 that blood removed from an animal immediately after the perceptible 

 effect of a large dose of epinephrin has disappeared will cause a rise in 

 pressure if injected into a second animal. More recently, Auer and Melt- 

 zer(a) have shown that when epinephrin is administered hypodermatically 

 in the denervated ear of a rabbit, a well-marked local vasomotor reaction 

 promptly appears and persists for hours. 



From the data at present available no satisfactory conclusion can be 

 reached as to how epinephrin is normally disposed of. Indeed, the theory 

 is not excluded that the suprarenal glands themselves remove epinephrin 

 from the blood-stream when, after special stimulation, it appears there 

 in any appreciable concentration ; similarly, that the precursors of epi- 

 nephrin are taken up and metabolized to some inert form, which is then ex- 

 creted in low concentration by way of the circulation as urea is removed 

 from the liver. 



Effect of Acute Suprarenal Deficiency upon 

 Blood -Pressure 



Oliver and Schafer's "tonus theory" postulated that blood-pressure is 

 kept up to normal height by a constant discharge of minimal quantities 

 of epinephrin into the blood-stream, and resulting stimulation of the cardio- 

 vascular apparatus. If this were the case, it should follow, in view of the 

 evanescent reaction to injected epinephrin, that ligation of the supra- 

 renal veins would lead to a prompt fall of pressure. 



Strehl and Weiss put the matter to experimental test. Their experi- 

 ments were made upon rabbits. One suprarenal was first removed. The 

 vein leading from the intact gland Avas then occluded for a brief period 

 while arterial blood-pressure was being recorded. Characteristically, 

 blood-pressure at once was lowered as much as 10 to 25 mm. of mercury. 

 Upon release of the vein the pressure again returned to, or above, the 

 normal height, In some cases the glands were removed in toto. The 

 results, however, were not uniform. In certain animals no fall of pres- 

 sure occurred. The experiments were of very brief duration, the glands 

 being occluded for only a few seconds to two or three minutes. The graphs 



